Multiplex telegraph equipment



April 3, 1934. H. RASSOW MULTIPLEX TELEGRAPH EQUIPMENT Filed Oct. 1'7,1932 2 Sheets-Sheet l H. RASSOW MULTIPLEX TELEGRAPH EQUIPMENT Filed Oct.17, 1932 2 Sheets-Sheet 2 6y W 4, KITTOR/Vfy April 3, 1934.

S win W Patented Apr. 3, 1934 UNITED STATES PATENT OFFICE MULTIPLEXTELEGRAPH EQUIPIVIENT poration of Germany Application October 17, 1932,Serial No. 638,155 In Germany July 11, 1931 6 Claims. (Cl. 178-52) Myinvention relates to improvements in multiplex telegraph systems, andmore particularly for wireless operation with interference eliminationby repeated transmission of the same signal. The object of the inventionis to increase the economy of such systems. According to the state ofthe interference every signal is transmitted two or three times. Thecapacity of an apparatus is in consequence of this repetition of thesignals correspondingly reduced to one half or one third. The increaseof the correctness of the transmission of the messages thus causes areduction of the speed of operation.

Some embodiments of my invention are illustrated in the drawings affixedhereto and forming part of my specification.

The drawings show:

Fig. l, the principle of the mode of operation of such a multiplextelegraph system,

Fig. 2, an embodiment of my invention in diagrammatic representation,

Fig. 3, a more detailed representation of the transmission mechanismdiagrammatically shown in Fig. 2, and

Fig. 4, a more detailed representation of the receiving mechanism ofFig. 2.

in Fig. 1 of the drawings a half duplex operation over two channelsbetween the two stations A and B is diagrammatically illustrated. Atstation A is only shown the respective transmission mechanism and at thestation B only the receiving portion of the apparatus. In the case ofoperation over wires the two stations are connected by means of the linea through the brushes b1, b2 rotating in perfect synchronism with thetwo distributors V1, V2. In the case of wireless operation the twobrushes are connected to corresponding transmitting and receivingamplifiers. The distributors V1 and V: are subdivided into a number ofequal sectors which is a common multiple of the provided repeatedtransmission of the same signal. In the case illustrated, there areprovided 2 3=6 sectors since the transmission is to be effected by meansof two channels and each signal is to be sent three times. Each sector 1to 6 is again subdivided into five segments, not shown in this figure,in correspondence with the five units. In addition thereto there isprovided a seventh sector 81, s: which operates each revolution andtransmits a signal for the purpose of synchronizing the revolvingbrushes. The two perforated tape transmitters SI, Sn provided at thestation A transmit the telegraph signals to a transmission impulsestoring device CI and Cu where the impulses are stored up in accordancewith the triple emission of signals to be effected later on. The storingof the impulses may be effected mechanically, i. e. by means ofperforated tapes or strips, or electromagnetically, for example by relaychains, or electrostatically, for instance by condensers, or also byadjusting mechanical storage members by means of electromagnets. C1 isconnected to the sectors 1, 3, 5, the storing device Cu to SGCtOIS 2, 4,6 of the distributor V1. Each signal is thus sent three times over thebrush b1. As the brush b: of the receiving distributor V2 is insynchronism with the brush in, the signals received are correspondinglytransmitted to the receiving impulse storing devices Dr, D11 and bythese transmitted to the telegraph receiving apparatus E1, En forrecording or printing.

In order to render the operation of the teleraph plants more economicalmaximum telegraph speeds will be employed wherever possible. The speedaimed at in wireless operation is 150 Bauds. In actual operation atelegraph speed of only 6.5 letters per second=32.5 Bauds is obtained intelegraph apparatus operating according to the five-unit code. From thisresults a subdivision into a plurality of telegraph channels the numberof which stands in inverse ratio to the number of the multipletransmissions for the purpose of interference elimination, for examplein the case of double transmission three channels and in the case oftriple transmission two channels. In actual practice a maximum speed ofonly Bauds can, however, be relied upon for the present. The individualchannels would therefore be utilized to only about half theircapacity, 1. e. a telegraph speed of only three letters per secondobtained.

The object of my invention is to combine the two transmitters operatingon a channel each into a single transmitter, for the purpose ofrendering the operation more economical. The message to be transmittedis dispatched from one transmitter by means of two channels, in such amanner that the letters or signals at the odd places (1, 3, 5 and so on)in the sequence of the text to be transmitted are transmitted over theone channel, and the letters or signals at the even places (2, 4, 6 andso on) over the second channel and are recorded at the receiver bysuitable apparatus in the original order of succession.

By the combination of two transmitters,

This storing device 65 which both operate at a maximum telegraph speedof three letters per second each and call for two operators into atransmitter operating on two channels, one operator is saved without thecapacity of the plant being reduced, inasmuch as this single transmitteris now able to operate at a speed of six letters per second.

An embodiment of my invention is diagrammatically illustrated in Fig. 2of the drawings. It shows the combination of the two transmitters Sr, Snof Fig. 1 into a single transmitter by connecting in parallel theconnections of this transmitter to the storing devices Ci of the onechannel and to the storing device Cn of the other channel. In the samemanner the two receivers Er, E11 are replaced by a single receiver E.The arrangement of the distributors is identical with that already shownand described in Fig. 1. If it is now desired to transmit from station Ato station B the letters a, b, c, d, for example, the subdivision of thesignals sent takes place in such a way, that the letters a, c aretransmitted to the transmitting distributor V1 across the storing deviceC: of one channel, and the letters b, d across the storing device C1: ofthe other channel. At station B the signals received are transmitted tothe storing devices D1 and D1: by the distributor V2 in such a manner,that the letters a, c are transmitted to the storing device D1 and theletters 11, d to the storing device Du, while by means of a receivingapparatus E the recording or printing of the letters a, b, c, d takesplace in the correct order of succession.

In Figs. 3 and 4 of the drawings my invention, which is only showndiagrammatically in Fig. 2, is illustrated in greater detail. Fig. 3shows the transmitting mechanism, Fig. 4 the receiving mechanism of theplant diagrammatically illustrated in Fig. 2.

The transmitting apparatus shown in Fig. 3 consists substantially of aperforated tape transmitter S, the transmitting distributor V1, theimpulse storing devices Cl, C2, which are all mounted on a single axleadapted to be driven by the motor M1. The impulse storing devices C1, C2consist of contact drums or rollers and condensers or, bi, oz, in by thecharging of which the impulses are stored. The distributor V1, whichcontrols the transmitter relay SR, serves for dispatching the currentimpulses. The transmitter relay transmits in well known manner theimpulses as double current signals to the key relay of the wirelesstransmitter, from a which they are passed into the transmitting aerial.The distributor which is represented as contact disk with revolvingcontact arms, is on its periphery divided into six sectors I to VI offive segments 1 to 5 each.

Coupled in a certain gear ratio with the distributor rev'olve thecontact transmitters of the storing devices C1, C2. The determination'of the current combinations to be dispatched for the five-currentstep-code takes place by the tape key or feeler mechanism T. Into thismechanism is fed a perforated tape L prepared in known manner in a handpunching apparatus. The tape key mechanism T consists of five selectorlevers, one of which only is shown in Fig. 3. According to whether thepoint of the feeler lever encounters a perforation or a solid portion ofthe tape or strip the lever places itself against the contact of thebattery B connected with the negative or positive pole and closes forthis circuit a contact d1, d; 05 th storing devices C1, C1. At a certainmoment the brush of the distributor brush arm e comes in contact withthe segment 11, i. the segment 1 of the sector I, and connects it to thetransmitting relay SR through the undivided ring 0. Simultaneously thebrushes of the storing device brush arms e1, e2 bridge the contacts d1,dz, (1:, d1, (1'2, (1'3, with the undivided rings in, m of the storingdevices C1 C2. This now completes a circuit from the negative pole Bacross the selector lever T, contact d1, brush arm c1 and ring 01 of thestoring device C1, hence across segment 11, and ring 1: of thedistributor V1 to the transmitter relay SR, and causes this relay toemit the impulse which corresponds with the perforation in theperforated tape L. The repeated transmission required for theelimination of interferences is attained by the storage condensers a1,bl being at the same time connected to the selector lever T across thecontacts dz, d3. so that both condensers are negatively charged. Thetransmission ratio between distributor and storage device is fixed insuch a way that after 2% revolutions of the distributor brush e thestorage device brush arm e1 has moved to such an extent only that ittouches the contact (12. At the same moment the distributor brush is onthe segment III]. (segment 1 of the sector III). In this way a circuitis completed across the condenser b1, contact dz, ring in, segment I111,ring 0 and the transmitter relay across which the condenser b1discharges itself. This discharge current impulse has the same directionas the current impulse sent out before over the segment 1111. It thuscauses in the transmitter relay the second dispatch of the previouslyselected impulse. When the distributor brush arm c has again advanced by2 revolutions and the storing device brush arm e1 by the correspondingdistance, the condenser (ll discharges itself across the contact d3,ring '01, segment V1, ring 12 and the transmitter relay SR. This bringsabout the third dispatch of the same impulse. For the remaining selectorlevers of the tape key selector mechanism T corresponding contactmechanisms and storing devices are provided, not shown in the drawings;This has the consequence that the impulse combinations selected by thelever T are emitted over the segments 1 to 5 of the sector I, and thenof the sectors III and V. As soon as the distributor brush arm has leftthe segment Is, the selection of the combination of perforations isfinished and the repetition of the signals takes place independent ofthe perforated tape on other sectors. After completion of a revolutionof the distributor brushes 2. fresh signal can thus be selected oversector I. This does not take place over sector I, however, but oversector II. Previous to this in the course of the rotation of thedistributor a circuit is completed which passes from the positive poleacross the ring I, the contact g and the feed magnet m to the negativepole of the battery B, for the feed magnet 1n, whose armature n feedsthe perforated strip or tape L forward by one hole division. For storingthe freshly adjusted signal a further storing device C2 is provided,which like the storing device C1 cooperates with the segments I, III, Vand the segments II, IV and VI. The circuit for the storing device C2 iscompleted by the brush e2. The contact segments d'1, d'2, d: of thestoring device C2 show in their arrangement a phase displacement incomparison with the arrangement of the corresponding contact segments ofthe storing device C1.

As described before the circuit is then as follows: negative pole of thebattery B across the selector or lever, contact d1, brush arm e2, ring'02 of the storing device C2, hence across segment I11 and ring of thedistributor V1 to the transmitter relay SR. In this way it is renderedpossible, as already explained in the introduction to the specificationwith reference to Fig. 2, that a message is transmitted from atransmitter S across the two storing devices C1, C2 by means of twochannels K1, K1, in such a manner that the letters or signs standing inthe sequence of the text to be transmitted at the odd places aretransmitted over the channel K1, the letters or signs at the even placesover the second channel K2.

Fig. 4 of the drawings illustrates the receiving arrangement. Thisarrangement consists of a receiving relay E, the receiving distributorV2 with the storing devices D1. D2, which are all mounted on a commonshaft and are operated by the motor M2. The arriving signals are firstreceived in the wireless receiver, amplified and in the rectified statefed to the receiving relay. This relay cooperates with the receivingdistributor V2 and the receiving storing devices D1, D2, theconstruction of which is similar to the corresponding parts of thetransmitter. The receiving distributor V1 is exactly as the sendingdistributor V1 subdivided by six sectors with five segments each and thetransmission ratio as well as the mutual position of the brush arms ofthe receiving distributor and the receiving storing device are identicalwith those of the transmitter. By the provision of special mechanism tobe described later on care is taken, that the brush arm c of thereceiving distributor V2 always revolves synchronously and in phasecoincidence with the brush arm e of the transmitting distributor V1. Atthe moment when the transmitter dispatches an impulse over the segmentI1 and the receiving relay E is reversed in correspondence with thisimpulse, the brush arm 0 of the receiving distributor V1 bridges thesegment I1, while the storing device brush arm 01 is located upon thecontact b1, and in this way a circuit is closed from the armature of thereceiving relay across the ring 1', segment I1, ring i1 of the storingdevice D1, brush arm 01, contact In to the condenser F1, the secondcoating of which is permanently connected to the negative pole of thebattery B2. From the drawings it will be readily gathered that onecontact of the receiving relay E is connected to the positive pole, andthat the other is insulated, however. The condenser F1 is thus chargedthen only if the segment I1 of therelay armature is connected to thepositive contact when the distributor brush 1 sweeps over it. Sincedistributor and the storing device brush arm 0, c1 of the receiveralways have the same position as those of the transmitter, the segment1111 is touched after 2 revolutions of the distributor brush c at themoment in which the transmitter dispatches the impulse consideredbefore, for the second time. The brush arm of the storing device has nowmoved up to the contact hz so that the condenser F1 is connected to thearmature of the receiving relay for the second time. This also happensacross contact h: if after further 2 revolutions the distributing brusharm 01 passes on to the segment V1 and the transmitter dispatches thesame impulse for the third time. It is now obvious that the condenser ischarged if during the three switching operations the relay armature wasconnected to the positive contact at least once; it is however notcharged if the armature of the receiving relay made contact with theinsulated contact every time. In this way results an evaluation of thereception, as called for by the interference elimination systemaccording to the Verdan system employed here, in an extraordinary simplemanner. In correspondence with the cooperation of the receivingdistributor V1 with the storing device D1. the receiving distributor V:cooperates with the storing device D1. Exactly in the same manner as thecircuit between V: and D1 is completed through the segments I, III, andV, the corresponding circuit with the storing device D2 is completedthrough the contact segments II, IV and VI.

The receiving distributor leads the impulses received forward to theprinting mechanism G. The adjustment of the printing relay DR for thepurpose of converting the impulses received into type printing accordingto the state of the condensers F1, F2 causes no diificulties. Shortlybefore the moment in which the third transmission from the sector V istaken up. the printing relay DR receives from the ring 1 of thedistributor V2 across contact 11. a current impulse which reverses it tothe negative side. Shortly after the third transmission the storingdevice brush arm i1 connects the condenser F1 across the contact ha andthe contact R to another winding of the printing relay DR. If thecondenser had then not been charged. the relay armature remains on theadjusted side: if the condenser had been charged, however, the armatureis reversed to the signal side. The identical equipment is of coursealso provided for the remaining impulses of each fiveunit signs so thatthe combination of perforations selected in the selector T of thetransmitter S is transmitted to the adjustment of the five printingrelays under elimination of the interferences. Only one of the typeprinting relays is illustrated in the drawings. The position of thesefive printing relays is employed for the selection of the type to beprinted as in the standard type printing apparatus. It now only remainsnecessary to release the printing mechanism for carrying out a printingprocess, which takes place during the further rotation of thedistributor brush arm 0 across the contact g. The maintenance of thesynchronism between the transmitter and the receiver is of greatimportance. To start with, it is obvious, that for a good coincidence ofthe phase position between the distributors V1 and V2 the maintenance ofa constant speed at the transmitter is a necessity. This constant speedis attained by a local synchronization. From the Figures 3 and 4 it willbe gathered that a direct current motor M1, M2 serves for the drive ofthe distributors and the storing devices. With the motor is directlycoupled a synchronous motor N1, N2, which is connected with a tuningfork generator G1, G2. The oscillating tuning fork generates analternating voltage of constant frequency, which is amplified and fed tothe synchronous motor. The synchronous motor temporarily operates assynchronous member and prevents variations of the speed, which wouldotherwise be produced by voltage fluctuations at the direct currentmotor, temperature rises, variations in the friction and the like.

In order that the receiver may adjust itseli: in accordance with thetransmitter, it is necessary that the transmitter should transmit asignal for the phase position. For this purpose there are mounted on theperiphery of the transmitter distributor V1 in addition to the thirtysegments of the six condensers two special segments pi, pa which arepermanently connected to the negative or the positive pole respectivelyof the source of current. Across these segments issues, independent ofthe signs which are dispatched over the other segments, during eachrevolution a phase sign The reversal from to is then for the receiverthe time signal which indicates that at that moment the transmitterdistributor starts a fresh revolution.

At the receiver a definite speed is attained exactly as in the case ofthe sender by the tuning fork generator G2 and the synchronous motor M1with the direct current motor M2. The frequency of this tuning fork is,however, set a little higher than that of the transmitter, so that theshaft of the receiving distributor leads in relationto the shaft of thetransmitter. To maintain the correct phase position, it is thereforenecessary to turn the receiving distributor back at certain intervals.This is eifected in the following manner: In correspondence with thesegments'for the phase signal of the transmitter the receiver islikewise fitted with two segments n, m. The segment 91 is insulated,while the segment in is connected to the winding of a sensitive relay KR(correction relay), the other end of which is permanently connected tothe negative pole. When the phase position of the transmitter andreceiver brush arms is identical, the passage from the contact 1); tocontact m takes place at the transmitter, i. e. the reversal from thesignal current to the disconnecting current at the transmission relayand at the receiving relay at the moment in which the receiving brushalso passes from segment pi to segment 112. During the sweeping of thebrush over the insulated segment n the armature of the receiving relayis thus connected to the voltage. During the sweeping of the brush oversegment p: the armature touches the insulated contact, so that in bothcases no circuit is completed for the correction relay KR. During thecourse of the further revolutions the receiving distributor leads,however, so that then the brush is already on segment in while thearmature of the receiving relay is still on the signal side, and is thusconnected to the voltage. The correction relay KR thus receives a shortcurrent impulse whose duration is determined by the amount of the leadof the receiver. At a definite amount of lead the correction relayresponds. From the armature of the correction relay is operated thecoupling magnet KM, which releases the coupling connected to thedistributor drive for one revoluti on. Together with the couplingrevolves a gearwheel Z which meshes with a toothed rim on the peripheryof the stator of the synchronous motor. The response of the correctionrelay KR thus causes a partial rotation of the stator of the synchronousmotor by an amount determined by the gear ratio. The rotation takesplace in such a direction, that the displacement of the phase positionof the rotor connected therewith causes a setting back oil thedistributor brush arm. After the setting back has been effected thedistributor performs a number of revolutions until the lead of thereceiver has again attained such an amount that the correction relay KRresponds.

In operation the frequency of the receiver tuning fork is so adjustedthat one setting back falls to each 8 to 9 distributor revolutions. Ifatmospherics exist these cause a change-over of the receiving relay tothe insulated contact. This is quite immaterial as long as the lead ofthe receiver has not yet attained the amount necessary for setting itback. If this amount of lead exists, however, the setting back isrendered impossible by an interference falling on the phase signal. Itmay in some cases happen that the phase signal is interfered with duringtwo or even three successive revolutions. It is, however, obvious thatthe further lead of the receiver then developing is not objectionable,as it is unequivocally fixed by the adjustment of the tuning fork. Thereceiver is in undisturbed operation set back after about each 9revolutions without the reception of the messages being interfered with.It is thus obvious that the synchronous run is fully ensured even in thecase of strongest in terferences with the reception.

What I claim as my invention is:

l. In a multiplex telegraph system of the type wherein each signalcharacter impulse is transmitted a plurality of times for overcomingstatic and/or interference, the method of communication from a singletransmitter located at a transmitting station which comprises sendingfrom said transmitter signal character impulses to different circuits atthe transmitting station, storing said impulses in each of saidcircuits, transmitting said impulses from each of said circuitsalternately over a single channel, and repeating the transmission ofsaid last impulses a plurality of times.

2. In a multiplex telegraph system, the method of communication betweena single transmitter and a single receiver which comprises transmittingfrom said single transmitter odd numbered signal character impulsesaccording to their chronological order of occurrence over one circuitand even numbered signal character impulses over another circuit,utilizing a single channel which is common to both of said circuits forsaid odd and even numbered impulses and repeating the transmission ofthe character impulses over said single channel.

3. In a multiplex telegraph system, a first distributor, a seconddistributor and a third distributor, a transmission line coupled to saidfirst distributor, a perforated tape transmitter in circuit with saidsecond and third distributors and arranged to apply signal characterimpulses alternately to said second and third distributors, said firstdistributor having alternate portions thereof respectively connected tosaid second and third distributors whereby said transmission line iscoupled alternately to said second and third distributors successively.

4. In a synchronous multiplex telegraph system, a first distributor, asecond distributor and a third distributor, a transmission line coupledto said first distributor, a perforated tape transmitter in circuit withsaid second and third distributors and arranged to apply signalcharacter impulses alternately to said second and third distributors,said first distributor having alter.- nate portions thereof respectivelyconnected to said second and third distributors whereby saidtransmission line is coupled alternately to said second and thirddistributors successively, a receiver having three other distributorswhich are similarly related to said receiver as the distributors at saidtransmitter are related to said transmitter, the distributors at saidreceiver being in synchronous'relationship with the correspondingdistributors of said transmitter and in circuit with same.

5. In a multiplex telegraph system of the type wherein each'signalcharacter impulse is transmitted a plurality of times for overcomingatmospheric disturbances, a first distributor, a second distributor anda third distributor, a transmission line coupled to said firstdistributor, a perforated tape transmitter in circuit with said secondand third distributors and arranged to apply signal character impulsesalternately to said second and third distributors, said firstdistributor having alternate portions thereof respectively connected tosaid second and third distributors whereby said transmission line iscoupled alternately to said second and third distributors successively,and impulse storing means at each of said second and third distributorsfor repeating the same signal character impulses to said firstdistributor as said first distributor functions to repeatedly connectsaid transmission line to said second and third distributors.

6. A system as defined in claim 4, characterized in this, that saidimpulse storing means consist of condensers.

HORST RASSOW.

spending distributors of said transmitter and in circuit with same.

5. In a multiplex telegraph system of the type wherein each signalcharacter impulse is transtively connected to said second and thirddistributors whereby said transmission line is coupled alternately tosaid second and third distributors successively, and impulse storingmeans 5 mitted a plurality of times for overcoming atat each of saidsecond and third distributors for 80 mospheric disturbances, a firstdistributor, a secrepeating the same signal character impulses to nddistributor and a third distributor, a transsaid first distributor assaid first distributor funcmission line coupled to said firstdistributor, a tions to repeatedly connect said transmission lineperforated tape transmitter in circuit with said to said second andthird distributors.

0 second and third distributors and arranged to ap- 6. A system asdefined in claim 4, characterized $5 ply signal character impulsesalternately to said second and third distributors, said firstdistributor having alternate portions thereof respecin this, that saidimpulse storing means consist of condensers.

HORST RASSOW.

CERTIFICATE OF CORRECTIDN.

Patent No. 1,953,658. April 3, 1934.

HORST RASSOW.

It is hereby certified that error appears in the printed specificationor the above numbered patent requiring correction as follows: Page 5,line 85, claim 6, for the claim reference numeral "4 read 1; and thatthe said Letters Patent should be read with this correction therein thatthe same may conform to the record or the case in the Patent Office.

Signed and sealed this 1st day of December, A; D. 1936.

Henry Van Arsdale (Seal) Acting Commis ioner of Patents,

